The present invention relates to a distributor for distributing a signal received by an antenna to a tuner module having a plurality of input portions, further in details, relates to a distributor preferably used in a case of connecting a single antenna to a tuner module for detecting connection or the antenna by feeding back a drive voltage of the antenna inputted from one input portion to other input portion and a broadcast signal receiving system using the same.
In recent years, there is proposed a satellite radio broadcast by transmitting to broadcast a signal including vocal information from an artificial satellite orbiting an earth orbit. Currently, in the United States, there is proposed such a satellite radio broadcast by XM Satellite Radio Corporation. In the satellite radio broadcast, a signal transmitted from an artificial satellite can be received in a wide area on the earth and therefore, attention is attracted thereto since the satellite radio broadcast is preferable not only for use of receiving and herring the broadcast by installing a receiver at a fixed location of a general household or the like but also for use of receiving and herring the broadcast by mounting a receiver to a moving body (for example, a vehicle body) or, for example, an automobile or the like.
In a vehicle-mounted receiving system for receiving satellite radio broadcast, both of satellite radio broadcast and ground radio broadcast which has conventionally been used widely are received by a single tuner module for the purpose of reducing a number of parts to achieve low cost.
According to such a vehicle-mounted receiving system, as shown in FIG. 5, a tuner module 101 having a first input portion 110 connected to a satellite wave antenna for receiving satellite radio broadcast, a second input portion 111 connected to a ground wave antenna for receiving ground radio broadcast and input/output terminals 112 connected to respective portions on a side of the receiver 100 are provided in a receiver 100 which is mounted to a vehicle. Further, the tuner module 101 includes an antenna detecting circuit 113 for detecting that the respective antennas are connected by inputting a drive voltage of an antenna 120 inputted from the first input portion 110 is fed back through the antenna to input from the second input portion 111.
According to the related tuner module 101, in a state that a satellite wave antenna and a ground wave antenna are respectively connected to the first input portion 110 and the second input portion 111, a drive voltage (drive power) inputted from the input/output terminals 112 is outputted to the respective antennas Via the first input portion 110 to be fed back from the respective antennas to the second input portion 111. Further, the antenna detecting circuit 113 detects that the respective antennas are normally connected, thereby the tuner module 101 is normally operated under the state (for example, see JP-A-2003-151377).
The related tuner module 101 is normally operated as described above when the satellite wave antenna and the ground wave antenna are respectively connected to the tuner module 101 in a state that the antenna module having both of the satellite wave antenna and the ground wave antenna is connected to the tuner module 101, for example, as shown in FIG. 5. However, when a single antenna for receiving only either one of a satellite wave or a ground wave is connected to the tuner module 101, a voltage is not applied to a side of the antenna detecting circuit 113 and therefore, connection of the antenna is not detected and the tuner module 101 cannot be operated normally. When a single antenna is used, there is a case in which a tuner module in correspondence with the single antenna needs to use to bring about an increase in fabrication cost.